JP2609306B2 - High-temperature carbonization gas heating method in continuous coke production equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a coke for metallurgy by carbonizing formed coal using an upright type carbonization furnace using a combustible gas as a heat medium. The present invention relates to a method for heating a high-temperature carbonized gas as a gas.

[Conventional technology]

Binder (coking agent) to coking coal made from steam coal
, Pressurized and molded to form molded coal, put it into an upright continuous carbonization furnace, and produce coke for metallurgy. ~
178 pages, "Iron and Steel Industry", August 1984, pp. 115-121.

FIG. 6 shows an equipment flow of the molded coke manufacturing equipment. The formed coal 2 produced in the formed coal production facility 1 is introduced into the upright continuous carbonization furnace 3 from the top thereof. The upright continuous carbonization furnace 3 is provided with a high-temperature carbonization gas 4 introduced from below.
And a low-temperature carbonization gas 5 introduced from an intermediate portion. Molded coal 2 introduced from the furnace top
Is heated and carbonized by a low-temperature carbonization gas 5 and then a high-temperature carbonization gas 4 at an appropriate rate. The obtained coke descends to a cooling zone below the upright continuous carbonization furnace 3, is cooled to about 130 ° C. by the cold gas 6 blown from the bottom, and is cut out from the discharge device 7 as carbonized coke 8.

The high-temperature carbonized gas 4 and the low-temperature carbonized gas 5 used as a heating medium for heating the formed coal 2 are flammable COG generated as by-products during the production of formed coke. That is, the gas generated by carbonization of the formed coal 2 rises in the upright continuous carbonization furnace 3 together with the high-temperature carbonization gas 4 and the low-temperature carbonization gas 5 blown into the furnace, and the sensible heat recovery device 9 The gas is sent to the dust collector 11 via the gas cooler 10. Dust collector
After the dust is removed at 11, a part of the generated gas is sent to a by-product recovery facility 13 as a recovered gas 12, and is used as a COG fuel after purification and desulfurization.

Most of the remaining generated gas is sent as circulation gas 14 to the gas circulation equipment. The gas circulation equipment is provided with a high-temperature gas pipe 15, a low-temperature gas pipe 16, and a cold gas pipe 17 to circulate the circulating gas 14 and blow it into the upright continuous dry distillation furnace 3. The high-temperature gas pipe 15 is provided with a gas heater 18 for heating the circulating gas 14 to a predetermined temperature and blowing it as a high-temperature carbonization gas 4 into the upright continuous carbonization furnace 3. On the other hand,
The low temperature gas pipe 16 is provided with a heat exchanger 19 and an ejector 20, and after adjusting the temperature of the circulating gas 14,
It is blown into an upright continuous carbonization furnace 3 as a low-temperature carbonization gas 5 at ~ 650 ° C.

As the gas heater 18, as shown in FIG. 7, a gas heater having a structure similar to that of an external combustion type hot blast stove as one of blast furnace facilities is used. That is, the gas heater 18 is
21, two regenerative furnaces 22a and 22b, switching valves 23a to 23h, and various pipes connecting these. In the combustion furnace 21, the mixed gas is constantly burned, and the combustion exhaust gas is transferred to the switching valve 23.
It is supplied to either one of the heat storage furnaces 22a or 22b by switching c or 23d.

For example, when the switching valve 23c is opened and the switching valve 23d is closed to send the combustion exhaust gas to the heat storage furnace 22a, the retained heat is given to the heat storage brick of the heat storage furnace 22a. And about 300 ℃
The exhaust gas whose temperature has been lowered is discharged from the chimney 25 via the exhaust gas conduit 24. At this time, the circulating gas 14 is introduced into the other heat storage furnace 22b from the cold gas pipe 26 via the switching valve 23h. The circulating gas 14 is heated by the heat storage bricks of the heat storage furnace 22b, heated to a high temperature of about 950 ° C., and supplied to the upright continuous carbonization furnace 3 as the high-temperature carbonization gas 4.

After a lapse of a predetermined time, the switching valves 23a to 23h are switched, the circulating gas 14 is introduced into the heat storage furnace 22a, and the temperature is increased. As described above, by switching the switching valves 23a to 23h, the heat storage furnaces 22a and 22b are switched between the heat storage period and the blowing period at a cycle of about 30 minutes, and the high temperature carbonized gas 4 heated to a predetermined temperature is obtained.

[Problems to be solved by the invention]

When heating the circulation gas 14 using the gas heater 18,
The temperature of the obtained high-temperature carbonized gas 4 is not constant. That is, in the initial stage of switching between the heat storage furnaces 22a and 22b, the temperature of the high-temperature carbonized gas 4 obtained also increases because the heat storage bricks heated during the heat storage period retain a large amount of heat. However, as the heat exchange between the heat storage brick and the circulation gas 14 progresses, the amount of heat held by the heat storage brick decreases, and the temperature of the high-temperature carbonized gas 4 decreases. The fluctuation of the temperature of the high-temperature carbonized gas 4 and the interruption of the gas at the time of switching the regenerative furnace have an adverse effect on the furnace condition of the upright continuous carbonized furnace 3, making it difficult to control the operating conditions.

In addition, the switching valves 23a to 23h have high heat resistance due to contact with high-temperature combustion exhaust gas of about 1200 ° C and a flammable component in the fluid used. Required. Moreover, these switching valves 23a to 23h
Since the opening and closing operation mistakes can lead to gas explosion, there is a need for attached, N ₂ purge, etc. of the safety device to the control equipment.

In order to solve such problems, circulating gas 14
A method in which heating is performed by an electric heater is considered. But,
In order to heat a large amount of the circulating gas 14 to a high temperature, an electric heater having a large capacity is required, and the burden on facility costs and operating costs increases. Further, it is conceivable to burn a part of the combustible components contained in the circulating gas 14 in the middle of the high-temperature gas pipe 15 and raise the temperature of the circulating gas 14 to obtain the high-temperature carbonized gas 4 (Japanese Patent Laid-Open No. -62205, JP-A-54-127903, etc.).

However, the temperature of the circulating gas 14 after leaving the dust collector 11 has dropped to near room temperature, and it is necessary to burn a large amount of combustible components to raise the temperature to a high-temperature dry distillation gas 4 of about 900 to 950 ° C. It is. As a result, a large amount of water is contained in the high-temperature carbonization gas 4 as a combustion reaction product, which has an adverse effect on the carbonization reaction of coal in the upright continuous carbonization furnace 3 and lowers the quality of the produced coke. Moreover, since the self-combustion is not sufficiently performed, the high-temperature carbonized gas 4 at a predetermined temperature cannot be obtained stably, and the furnace condition becomes unstable.

Therefore, the present invention improves the heating method for converting the circulating gas into a high-temperature carbonized gas, thereby continuously raising the high-temperature carbonized gas at a constant temperature to an upright-type continuous carbonized gas without causing a rise in equipment costs and operating costs. The objective is to supply coke to a furnace and produce coke of excellent quality under stable furnace conditions.

[Means for solving the problem]

In order to achieve the object, the high-temperature carbonized gas heating method of the present invention is characterized in that a high-temperature carbonized gas and a low-temperature carbonized gas are blown as a heat medium into a lower portion and an intermediate portion of an upright continuous carbonization furnace, respectively, and the formed coke is carbonized. In manufacturing, in the circulation path of the generated gas discharged from the upright continuous carbonization furnace, the generated gas is primarily heated to 500 ° C. or more by an indirect heat exchanger, and then the generated gas is heated by the upright continuous carbonization furnace. An oxygen-containing gas having a temperature of 500 ° C. or more is blown into the flow path immediately before being blown into the gas, and 10% of the combustible components contained in the generated gas are blown.
The temperature of the generated gas is raised by burning the following, and the generated gas after the temperature rise is blown into the upright continuous carbonization furnace as the high-temperature carbonized gas.

[Action]

After leaving the dust collector 11 shown in FIG. 6, the circulating gas 14 has dropped to near normal temperature. When the temperature of the circulating gas 14 is increased to about 900 to 950 ° C., which is required as the high-temperature carbonization gas 4, by burning the combustible components contained in the circulating gas 14, for example, the moisture contained in the burned gas is reduced. Rise to about 15%. This water content greatly affects the strength of coke obtained by carbonization. However, the present inventors have clarified that there is an upper limit in the water content that causes a decrease in the strength of coke. The upper limit depends on the properties of the coal 2 and the target temperature of the high-temperature carbonized gas 4,
%.

Thus, in the present invention, the circulating gas is heated in advance by an indirect heat exchanger, so that the flammable gas burned to raise the temperature of the circulating gas 14 to a temperature required for the high-temperature carbonized gas 4 (for example, 900 to 950 ° C.). The proportion of ingredients has been reduced to less than 10%. As a result, even when the target temperature is set by the self-combustion of the circulating gas 14, the water content can be suppressed to the above-described upper limit of 10% or less. Therefore, even if the obtained high temperature carbonization gas 4 is blown into the upright continuous carbonization furnace 3, the coking reaction of the formed coal 2 can be maintained without any adverse effect on the furnace condition.

Here, the temperature of the circulating gas after the primary heating needs to be 500 ° C. or higher. When this temperature is 500 ° C. or higher, the amount of moisture contained in the high-temperature carbonized gas can be suppressed to an upper limit of 10% or less as a result of the combustion at the stage of injecting an oxygen-containing gas to burn combustible components. However, if the temperature after the primary heating is less than 500 ° C., the amount of combustible components to be burned in the next step increases, and as a result, the moisture content in the high-temperature carbonized gas 4 exceeds 10%, and the coke The reaction has a negative effect.

Further, it is necessary to preheat oxygen-containing gas for combustion such as air to 500 ° C. or more. Due to this preheating, diffusion between the circulating gas and the oxygen-containing gas is promoted, and the combustion reaction proceeds smoothly. Further, in order to maintain stable self-combustion, the combustion is started in a relatively oxygen-rich atmosphere. For this reason, an igniter arranged at a location where the ratio of oxygen-containing gas / circulating gas is 1.0 or more is used. With this igniter, combustion of the combustible component is easily started.

〔Example〕

Hereinafter, the features of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an upright continuous carbonization furnace incorporating a high-temperature carbonization gas heating mechanism according to the present invention, and ancillary equipment thereof. In this figure, components corresponding to those shown in FIG. 6 are designated by the same reference numerals, and their description is omitted.

The circulating gas 14 flowing through the high-temperature gas pipe 15 is an indirect heat exchanger.
At 27, it is heated to a temperature above 500 ° C. As the indirect heat exchanger 27, an indirect heat exchanger such as a recuperator is used. For example, a high-temperature gas is supplied to a high-temperature side pipe arranged so as to surround the flow path of the circulating gas 14 or meandering in the flow path, and the retained heat of the high-temperature gas is
Tell This high-temperature gas is exhaust gas obtained by burning BFG, COG, and the like. Note that the heating of the circulating gas 14 by the high-temperature gas is performed by heat conduction through the tube wall, and thus the maximum heating temperature is about 650 ° C.

On the downstream side of the indirect heat exchanger 27, an oxygen gas conduit 28 opens to the high-temperature gas pipe 15. A predetermined amount of an oxygen-containing gas 29 is blown into the circulating gas 14 after being primarily heated by the indirect heat exchanger 27 via an oxygen gas conduit 28. As the oxygen-containing gas 29, air, pure oxygen, oxygen-enriched air, or the like is used. A part of the combustible components contained in the circulating gas 14 are burned by the injected oxygen-containing gas 29, and the temperature of the circulating gas 14 is increased by the heat of combustion. At this time, the oxygen-containing gas 29 is previously heated to a temperature of 500 ° C. or more by the heater 30 in order to smoothly perform the combustion reaction.

The opening position of the oxygen gas conduit 28 with respect to the high-temperature gas pipe 15 is determined at a position near the tuyere of the upright continuous carbonization furnace 3. As a result, the amount of combustion heat dissipated and the hot gas piping 15
The range of adhesion of soot to the inner wall can be reduced.
Although FIG. 1 shows one oxygen gas conduit 28, a plurality of oxygen gas conduits 28 can be opened in the high-temperature gas pipe 15 without being restricted by this.

FIG. 2 shows an example. In the case of this example, the high-temperature gas pipe 15 is branched corresponding to the plurality of tuyeres 3a provided in the upright continuous carbonization furnace 3, and the oxygen gas pipes 28 are connected to the individual branch pipes 15a.
To open. When the self-combustion is performed in the branch pipe 15a in this manner, the temperature drop due to heat dissipation while the high-temperature gas flows through the high-temperature gas pipe 15 is eliminated, and the temperature of the gas blown into the tuyere 3a is stabilized.

FIG. 3 shows an oxygen gas pipe 28 to the hot gas pipe 15.
1 shows an example of the opening. In this example, as shown in FIG.
An oxygen gas conduit 28 is opened at 15a. Further, as shown in FIG. 3B, an oxygen gas conduit 28 is opened in a tangential direction of the large diameter portion 15a. Thereby, the oxygen-containing gas 29 that has flowed into the large-diameter portion 15a from the oxygen gas conduit 28 flows as a vortex along the inner wall of the large-diameter portion 15a. On the other hand, hot gas piping
The circulating gas 14 after the primary heating sent from 15 is diffused in the large-diameter portion 15a having a large channel cross-sectional area. Therefore, the circulation gas 14 and the oxygen-containing gas 29 are sufficiently mixed, and the combustion proceeds smoothly. Also, at the exit from the large diameter part 15a,
Since the gas after combustion is compressed, it is sent out as a high-temperature carbonized gas 4 having a uniform temperature distribution.

Here, an igniter 31 is provided at a location where the oxygen gas conduit 28 opens to the large-diameter portion 15a. At this point, the ratio of the oxygen-containing gas / circulating gas is 1.0 or more, so that the flammable component of the circulating gas is quickly ignited. In addition,
The igniter 31 is located near the opening of the oxygen gas conduit 28 as long as the oxygen-containing gas 29 ejected from the oxygen gas conduit 28 is not sufficiently diffused into the circulating gas 14 and the oxygen content is still high. Can be provided.

FIG. 4 is a view for explaining an example of a mechanism for controlling the flow rate of the oxygen-containing gas 29 supplied from the oxygen gas conduit 28 to the high-temperature gas pipe 15 based on the target temperature of the high-temperature carbonized gas 4.

An orifice 32 is provided in the middle of the oxygen gas conduit 28, and a pressure difference between the oxygen-containing gas 29 flowing through the oxygen gas conduit 28 before and after the orifice 32 is detected by a differential pressure oscillator 33 and a flow meter 34 is provided.
And the flow rate of the oxygen-containing gas 29 is detected. The detected flow rate is input to the calculator 35. On the other hand, hot gas piping
15 is provided with a thermometer 36 such as a thermocouple.
The temperature of the high-temperature carbonized gas 4 flowing through the high-temperature gas pipe 15 detected by the above is input to the calculator 35.

The computing unit 35 compares the detected temperature value from the thermometer 36 with a set value. If the detected temperature is lower than the set value,
A command to open the flow control valve 37 is output to the valve opening regulator 38 so as to increase the flow rate of the oxygen-containing gas 29 flowing through the oxygen gas conduit 28. As a result, combustion in the vicinity of the opening 28a of the oxygen gas conduit 28 is promoted, and the temperature of the high-temperature carbonized gas 4 increases. On the other hand, when the temperature detected by the thermometer 36 is high, the flow control valve 37 is throttled to reduce the supply amount of the oxygen-containing gas 29 and suppress the combustion reaction. Thus, the temperature of the high-temperature carbonization gas 4 blown into the upright continuous carbonization furnace 3 is kept constant. The high-temperature gas pipe 15 is provided with an oxygen analyzer 39, and the oxygen content of the high-temperature carbonized gas 4 detected by the oxygen analyzer 39 is recorded in the oxygen recorder 40.

The following table shows operating conditions when the circulating gas 14 coming through the dust collector 11 is heated to the high-temperature carbonized gas 4 at the target temperature by primary heating and self-combustion. The circulating gas 14 is composed of 53% H ₂ , CH ₄ 1
9.2%, CO3.7%, N ₂ 19.1%, CO ₂ 3.6%, C ₂ H ₄ 0.2%, C ₂ H ₆ 1.3
% Of the circulating gas 14 is sent to the indirect heat exchanger 27 in a required amount, and the circulating gas 14 is primarily heated by the indirect heat exchanger 27. And oxygen-containing gas for secondary heating
It is assumed that the air preheated to 600 ° C. by the heater 30 is used as 29.

As is clear from Table 1, the circulating gas 14 was
Heating to 500 ° C. or higher requires less combustion heat to be generated in the next heating step, so that the water content in the obtained high-temperature carbonized gas 4 can be suppressed to the upper limit of 10% or less.

FIG. 5 is a graph showing the effect of the water content contained in the high-temperature carbonization gas 4 on the coking reaction in the upright continuous carbonization furnace 3. As is clear from FIG. 5, the high-temperature carbonization gas 4 blown into the upright continuous carbonization furnace 3
As the moisture content of the coke decreases, the strength of the obtained coke increases. This tendency is particularly noticeable when the final carbonization temperature is increased. In this regard, in this embodiment, since the high-temperature carbonized gas 4 having a low water content is used, the strength of the produced coke ▲ DI ¹⁵⁰ ₁₅
▼ surely exceeded the target value of 84. Therefore, the rate of pulverization at the stage of transporting the coke and charging the blast furnace was small, and the blast furnace could be operated under stable conditions.

〔The invention's effect〕

As described above, in the present invention, a high-temperature carbonization gas blown into an upright continuous carbonization furnace of a continuous coke manufacturing facility, after primary heating of a circulating gas by an indirect heat exchanger,
It is obtained by heating to the target temperature with the combustion heat generated by the combustion of the combustible components. Therefore, the amount of combustible components consumed at the time of secondary combustion is reduced, a high-temperature carbonized gas having a low moisture content is obtained, and it becomes possible to coke coal without adversely affecting the furnace condition. Moreover, unlike the case of using a hot blast stove provided with a regenerative furnace, a high-temperature carbonization gas at a constant temperature can be continuously obtained, and disturbance to the furnace temperature distribution of the upright continuous carbonization furnace is reduced. Also,
Since high-temperature carbonized gas with the target temperature can be obtained without the need for a complicated and expensive hot-air stove equipped with switching valves and piping, the equipment itself becomes simpler, and the burden on equipment and operation costs is reduced. You.

[Brief description of the drawings]

FIG. 1 is a flow chart showing a continuous coke manufacturing facility incorporating a heating mechanism according to the present invention. FIG. 2 shows an example in which an oxygen gas conduit is opened in each branch pipe of a high-temperature gas pipe. The figure shows the open state of the oxygen gas conduit with respect to the high-temperature gas pipe, FIG. 4 shows a mechanism for controlling the temperature of the high-temperature carbonized gas to a target value, and FIG. It is a graph showing the effect.
On the other hand, FIG. 6 is a flow chart showing a conventional continuous coke making facility, and FIG. 7 shows a hot blast stove type gas heater incorporated therein. 3: Upright continuous carbonization furnace, 4: High temperature carbonization gas 5: Low temperature carbonization gas, 8: Carbonization coke 14: Circulation gas, 27: Indirect heat exchanger 28: Oxygen gas conduit

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Hiroshi Nakama, Inventor 1-1 1-1 Emitsu, Yawatahigashi-ku, Kitakyushu-shi, Fukuoka Prefecture Inside the Nippon Steel Corporation 3rd Technology Research Institute (72) Inventor Yoshimitsu Konno Fukuoka 1-1-1, Edamitsu, Yahata-Higashi-ku, Kitakyushu City Inside Nippon Steel Corporation Equipment Engineering Division (56) References

Claims (1)

(57) [Claims] 1. A high-pressure carbonization gas and a low-temperature carbonization gas are blown into a lower portion and an intermediate portion of the upright continuous carbonization furnace, respectively, as a heat medium, and carbonized coal is carbonized to produce molded coke. In the circulation path of the generated gas, after the generated gas is primarily heated to 500 ° C. or more by an indirect heat exchanger, the generated gas has a temperature of 500 ° C. or more in a flow path immediately before being blown into the upright continuous carbonization furnace. Oxygen-containing gas is blown, and 10 of the combustible components contained in the generated gas are blown.
% Of the generated gas by burning less than
A method for heating a high-temperature carbonized gas in a continuous coke manufacturing facility, wherein the generated gas after the temperature increase is blown into the upright continuous carbonization furnace as the high-temperature carbonized gas.